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DEC (SPC700): Difference between revisions
From SnesLab
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* [[DEX]] | * [[DEX]] | ||
* [[DEY]] | * [[DEY]] | ||
* [[SBC (SPC700)]] | |||
* [[SBC]] | |||
=== External Links === | === External Links === | ||
Revision as of 09:43, 16 July 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Accumulator | 9C | 1 byte | 2 cycles | ||||
| Direct Page | 8B | 2 bytes | 4 cycles | ||||
| Direct Page Indexed by X | 9B | 2 bytes | 5 cycles | ||||
| Absolute | 8C | 3 bytes | 5 cycles | ||||
| Implied (type 1) | 1D | 1 byte | 2 cycles | ||||
| Implied (type 1) | DC | 1 byte | 2 cycles | ||||
| Flags Affected | |||||||
|---|---|---|---|---|---|---|---|
| N | V | P | B | H | I | Z | C |
| . | . | . | . | . | . | ||
DEC is an SPC700 instruction that decrements its operand by one.
Syntax
DEC A DEC dp DEC dp+X DEC !abs DEC X DEC Y
The above are official, but some people prefer alternate mnemonics like:
DEX DEY
See Also
External Links
- Official Super Nintendo development manual on DEC: Appendix C-7 of Book I
- anomie: https://github.com/yupferris/TasmShiz/blob/8fabc9764c33a7ae2520a76d80ed7220bb939f12/spc700.txt#L415